Undersea pressure sensitive actuator

ABSTRACT

A pressure sensitive actuator for use in underwater recovery systems. A diaphragm is selected so as to burst at a predetermined depth. Water entering the actuator, through the ruptured diaphragm, actuates a salt water battery which, in turn, fires a cartridge. The cartridge gases act upon a piston to displace an attached rod thereby actuating a high pressure valve causing inflation of flotation bags.

United States Patent Folden, Jr. et a]. [4 1 June 13, 1972 [54] UNDERSEA PRESSURE SENSITIVE [56] References Cited ACTUATOR UNITED STATES PATENTS 1 Inventor-S1 Virgil Fold, Falmouth; Jflhnny 3,101,733 8/1963 Lord Miller, J Fredericksburg. both of 3,266,669 8/1966 Vuyosevich ..222 5 [73] Asslgnee: The g: of m g as Primary ExaminerRobert B. Reeves represen y e mm o e a y Assistant Examiner.lames M. Slattery [22] Filed: April 27, 1970 Attorney-R. S. Sciascia and Thomas 0. Watson, Jr. [21] Appl. No.: 31,893 57 ABSTRACT A pressure sensitive actuator for use in underwater recovery [52] U.S. Cl ..222/3, 9/323 systems. A dia hragm is selected so as to burst at a predeter- [51] Int. Cl ..B67b 7/24 mined depth, water entering the actuator, through the ru [58] Field of Search ..222/3, 5, 386; 9/323, 325; tured diaphragm, actuates a salt water battery which, in turn,

137/68, 797 fires a cartridge. The cartridge gases act upon a piston to displace an attached rod thereby actuating a high pressure valve causing inflation of flotation bags.

1 Claim, 2 Drawing Figures PATENTEUJUN 13 m2 3. 689.31 1

sum 2 or 2 UNDERSEA PRESSURE SENSITIVE ACTUATOR STATEMENT OF GOVERNMENT INTEREST BACKGROUND OF THE INVENTION The present invention relates generally to pressure sensitive actuators and more particularly to such actuators that are sensitive to water pressure.

Oceanographic data is commonly retrieved through the use of underwater vehicles. Typically, these vehicles are unmanned and are towed by a surface ship. In the event that the towed vehicle or fish should break loose, it is often desirea' ble to attempt to retrieve it because of the cost of the sophisticated data collecting instrumentation on board.

lf there is no self-actuating retrieval system on board the fish", resort must be made to elaborate procedures involving the use of divers. Such procedures are often time consuming and expensive and, at great water depths, may prove to be impossible.

The use of an on-board recovery system, eliminates the necessity of resorting to undersea divers for retrieval. Such a system requires a water sensitive actuating device. Typical prior art actuating devices fall within three general classes. The first is actuated by the mere presence of water. Obviously, such a device has no application within the desired retrieval system. The second general class of actuators has a delay mechanism typically a water soluble plug which prevents actuation for a definite period of time. Such actuators would impose unnecessary time limitations and their use is, for that reason, undesirable. Finally, there are those actuators whose operation is initiated by hydrostatic pressure. Such devices have no inherent time limitation and may be set so that actuation is initiated at a water depth below that at which the fish is being towed. Should the fish break loose from the towing vehicle, it will sink to the point at which the hydrostatic pres sure is sufficient to actuate the recovery system and refloating will be accomplished.

A typical hydrostatic pressure initiated actuator is shown in the Bannister Pat. No. 2,687,54l. Such devices commonly have a membrane sealed gas container and a puncturing mechanism to pierce the seal and release the gas. The puncturing mechanism is frequently driven by a coil spring with the spring being maintained in a biased condition by a releasing mechanism.

To insure that the puncturing mechanism is driven with sufficient force to pierce the sealing membrane, a relatively heavy spring must be used. The use of such springs not only complicates assembly procedures but also requires a correspondingly heavy releasing mechanism which may cause a decrease in sensitivity. Further, a defect in the releasing mechanism may lead to the situation where the releasing mechanism is overcome by the force of the biased spring thus causing a premature initiation of the refloating system.

SUMMARY OF THE INVENTION The general purpose of this invention is to provide a recovery system actuator which is sensitive to hydrostatic pressure while eliminating the use of membrane sealed gas containers and puncturing mechanisms with the attendent coil spring. This is accomplished by providing a rupture disc which is selected to burst at a predetermined depth thus preventing initiation of the recovery system at lesser depths. Upon fracture of the rupture disc, water entering the actuator activates a salt water battery which, in turn, ignites a cartridge. The expanding gases from ignition of the cartridge act upon a piston to displace it and an attached rod. This rod is connected to a compressed gas control valve which controls the flow of gas to the reflotation system.

OBJECTS OF THE INVENTION Accordingly, it is an object of the present invention to provide a reliable actuator for an undersea recovery system.

Another object is to provide a recovery system actuator which responds to hydrostatic pressure.

A further object of the invention is the provision of a pressure sensitive actuator having no driving springs or puncturing mechanisms.

Other objects, .advantages and novel features of the invention will .become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial cutaway of an underwater vehicle employing an embodiment of the present invention; and

FIG. 2 is a partial cross section of a preferred embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates an underwater vehicle 11 with a deployed reflotation system employing the present invention. As shown, the reflotation system comprises compressed gas cylinders 12 connected by air lines to the control valve 13. Located adjacent the control valve 13 is the control valve actuator 14 of the present invention. Under the control of the control valve 13 and control valve actuator 14, compressed gas passes to the flotation bags 15 after passing through pressure reducing valves (not shown). The flotation bags 15 are here shown in their operative position. When not in use, the flotation bags 15 are within the underwater vehicle 11 with the openings in the sides of underwater vehicle 11 being closed by doors 16.

Referring now to FIG. 2, there is shown a preferred embodiment of the control valve actuator 14 of the present invention. The body of actuator 14 is generally cylindrical having an internal bore 18. Located with internal bore 18 and towards one end of actuator 14 is a rupture disc 19. While intact, rupture disc 19 maintains a water tight seal within internal bore 18.

Located towards the other end of actuator 14 is an internal cylinder portion designated at 21. 'Moveably mounted within cylinder 21 is piston 22 which has an extension in the form of actuating rod 23. 0" rings 24 mounted on the piston 22 and actuating rod 23 maintain the cylinder 21 in an air tight condition.

Located generally at the center of actuator 14 and within bore 18, is a salt water battery 26 electrically connected to cartridge 27. Cartridge 27 is mounted within insert 28 which together with 0 rings 29 maintains an air tight seal between bore 18 and cylinder 21.

Rupture disc 19 is held within bore 18 by a union 31. It is selected to rupture at a hydrostatic pressure corresponding to apredetermined water depth. Upon rupture, the seal maintained by rupture disc 18 is broken and water will flow within bore 18 to salt water battery 26. The water reaching salt water battery 26 will cause it to actuate and fire cartridge 27. The combustion gases from cartridge 27 will expand with cylinder 21 and create a force operating on piston 22. The increasing pressure with cylinder 21 will move piston 22 and cause a corresponding displacement of actuating rod 23 which is connected, through block 34 and lock nut 35, to a control valve 13 (see FIG. 1). Shear wire 36 acts to retain actuating rod 23 until such time as cartridge 27 is fired.

In operation, actuator 14 is placed within a refiotation system shown generally in FIG. 1. Rupture disc 19 is selected to rupture at a depth below that at which vehicle 1 l is desired to operate. Should the vehicle 11 break loose, and sink to the rupture depth, disc 19 will rupture and allow water to reach salt water battery 26. This will cause cartridge 27 to ignite and will lead to a displacement of actuating rod 23 through the combustion gases acting upon piston 22. Actuating rod 23 will operate upon the control valve 13 of FIG. 1 to allow compressed gases from the cylinder 12 to reach flotation bags 15 and inflate them. The door 16 will be ejected to allow the flotation bags 15 to expand outside the vehicle 11 to create a sutficient buoyancy to bring the vehicle 1 l to the surface.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings.

What is claimed is: i

l. A water pressure sensitive actuator for controlling the filling of flotation bags which comprises:

a nominally cylindrical body having an internal bore;

a pressure sensitive rupture disc located at one end of said body and making a water tight seal in said bore; said rupture disc being selected to rupture at a predetermined water depth;

a piston and an actuating rod operatively connected to said piston located generally at the other end of said body and moveably mounted within said bore for operating upon a control valve while maintaining a water tight seal at said other end of said bore;

a salt water battery and cartridge ignited by power from said battery located within said bore intermediate said rupture disc and said piston for imparting motion to said piston upon sensing the presence of water; and a shear wire passing through said actuating rod and said cylindrical body to retain the actuating rod in a fixed position until the cartridge is activated; whereby the pressure at a predetermined water depth will cause the rupture disc to rupture thereby allowing water to reach the salt water battery which fires the cartridge to impart motion to the piston and actuating rod to open the valve which controls the filling of flotation bags. 

1. A water pressure sensitive actuator for controlling the filling of flotation bags which comprises: a nominally cylindrical body having an internal bore; a pressure sensitive rupture disc located at one end of said body and making a water tight seal in said bore; said rupture disc being selected to rupture at a predetermined water depth; a piston and an actuating rod operatively connected to said piston located generally at the other end of said body and moveably mounted within said bore for operating upon a control valve while maintaining a water tight seal at said other end of said bore; a salt water battery and cartridge ignited by power from said battery located within said bore intermediate said rupture disc and said piston for imparting motion to said piston upon sensing the presence of water; and a shear wire passing through said actuating rod and said cylindrical body to retain the actuating rod in a fixed position until the cartridge is activated; whereby the pressure at a predetermined water depth will cause the rupture disc to rupture thereby allowing water to reach the salt water battery which fires the cartridge to impart motion to the piston and actuating rod to open the valve which controls the filling of flotation bags. 